US Bridges

Idfg Access Road over Salmon River

Fair

Lemhi County, Idaho · 13.9 N. 9.3 E. Challis · Structure no. 000000000032760

Built
1989
36 years old
Condition
Fair
inspected April 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
190 ft
2 main spans
Daily traffic
30
2023 count
Owner
State
Other State Agency

About this bridge

Idfg Access Road over Salmon River is a prestressed concrete stringer/multi-beam or girder carrying Idfg Access Road over Salmon River in Lemhi County, Idaho. It was built in 1989, so it is 36 years old, younger than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 30 vehicles a day, roughly 10% of them trucks, projected to reach 45 by 2039. The structure is 190 ft (57.9 m) long and 15 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesIdfg Access Road
CrossesSalmon River
Location13.9 N. 9.3 E. Challis
RouteState Lands Road 0
CountyLemhi County
StateIdaho
Coordinates44.70294, -114.04306
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating86 US tons
Inventory rating41 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length190 ft (57.9 m)
Longest span93 ft (28.3 m)
Deck width15 ft (4.6 m)
Roadway width13 ft (4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic30 (2023)
Projected traffic45 by 2039
Trucks10%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther State Agency
Maintained byOther State Agency
Historic statusHistorical significance not determinable at this time
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.6 million (2020 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Idfg Access Road over Salmon River built?

It was built in 1989, making it 36 years old in 2025.

What condition is Idfg Access Road over Salmon River in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in April 2024.

How much traffic does Idfg Access Road over Salmon River carry?

About 30 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is Idfg Access Road over Salmon River?

The structure is 190 ft (57.9 m) long with a longest span of 93 ft (28.3 m) and a deck 15 ft wide.

Who owns Idfg Access Road over Salmon River?

It is owned by the Other State Agency.